Cartridge fuse



S- 1927' LE ROY w. KELSAY CARTRIDGE FUSE Filed July 5. 1924 hw /0m za/PoW//m by AW] Patented Aug. 9, 1927.

UNITED STATESPATENT OFFICE.

LE ROY 11V. KEIiSAY, OF NEW YORK, N. Y., ASSIGNOR T0 WESTERN ELECTRICCOM- PANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

CARTRIDGE FusE.

Application filed July 5,

My invention relates to fuses and particularly to fuses of the cartridgetype.

The object of my invention is to provide a fuse of the type indicatedwhich may be cheaply aanufactured and which shall be eflicient inoperation.

Heretofore. it has been the practice to secure the end plugs to thecylindrical casing by screws, rivets, cement, or by spinning a ferruleinto agroove in the casing. These methods necessarily weaken thestructure of the fuse and involve expensive manufacturing operations.Again, the shrinking and swelling of the fibre tube, due to excessivedryness or moisture, causes an insecure condition in the types ofconstruction mentioned.

In acordance with this invention, tapered end plugs, the inner ends ofwhich are made of substantially the same diameter as the inside of thetube, are forced into the-ends of the insulating tube under pressure andsecurely fixed in position by metal ferrules spun against the outside ofthe tube. The plugs are preferably provided with fins or ribs to preventrelative turning of the shell and plugs. This arrangement provides arigid and durable construction wherein the end plugs will not be blownoff by the pressure of the gas generated when the fuses are blown, andwill not become loose as the fibre expands or contracts,due toatmospheric conditions.

Referring to the drawing Fig. 1 shows a fuse of this invention inpartial. longitudinal section, 1 indicates one of the end plugs,preferably of brass, the face of which has beenknurled or ribbed as at2. to prevent the plug from turning in theshell 8, and 3 designates themetal ferrule, the initial position of which before the spinningoperation being indicated by the dot and. dash outline 4. Numeral 5designates the threaded shank which with the nut 6 and washer 7constitute the binding post. Fig. 2 is a cross-sectional view of Fig. 1taken at line- 22.

In assembling the fuse, the fusible link 10 is fastened into one oftheend plugs,

1924. Serial No. 724,372.

preferably by soldering, and the fibre insulating cylinder 8 is forcedover this frustroconical plug under pressure.

The inner di ameter of the plug, being of substantially the samediameter as the inside of the tube, causes the end of the tube to expandas shown by numeral 9. Then the other end plug is slipped over the fusewire 10 and forced into the other end of the tube as shown at 9. Tocomplete the process, ferrules 3 are spun over the expanded ends of thefibre tube, thus locking the assembly, and the fuse wire is solderedinto place ll.

While I have shown the preferred em" bodiment of my invention, changesmay be effected therein without departing from the spirit or scopethereof, as set forth in the appended claims.

hat is claimed is:

1. In an electrical cartridge fuse, a hollow cylindrical casing, afusible link, frustro-conical contact plugs in the ends of said casingandsupporting said fusible link, said plugs being coneshaped and theirlargest diameter being greater. than the inside di' ameter of saidcasing and having external longitudinal ribs to engage the inside ofsaid. casing, and cup-shaped ferrules secured over the distorted ends ofsaid asing and including said plugs.

2. The method of making cartridge fuses which consists in forcingapertured tapered plugs into and expanding the ends of a hollowcylindrical tube, supportinga fusible. link in said plugs, and clampingcollars around thetube ends and plugs.

3. The method of making cartridge fuses which consists forcinglongitudinally ribbed frustro-conical end plugs into the ends of ahollow cylindrical fibre tube, the largest diameter of said plugs beinggreater than the inside diameter of said tube, and spinning metal capsover the expanded ends of said tube.

In witness whereof, I hereunto subscribe my name this 2 day of July, A.D. 1924.

, LE ROY W. KELSAY.

